Segment Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	$ 60,692,645	$ 57,357,442	$ 183,015,723	$ 177,663,291
Operating Profit	5,720,411	4,740,408	11,014,013	13,300,801
Interest expense	(420,377)	(310,507)	(974,536)	(918,897)
Other income	188,623	228,787	789,371	673,287
Income before income taxes	5,488,657	4,658,688	10,828,848	13,055,191
Operating Segments [Member] | Industrial Hardware [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	39,427,301	34,210,857	115,321,597	106,621,484
Operating Profit	3,419,052	1,832,203	6,369,647	7,116,732
Operating Segments [Member] | Security Products [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	14,169,694	16,918,909	45,355,397	49,926,265
Operating Profit	1,762,703	2,406,390	3,703,098	5,055,569
Operating Segments [Member] | Metal Products [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	7,095,650	6,227,676	22,338,729	21,115,542
Operating Profit	$ 538,656	$ 501,815	$ 941,268	$ 1,128,500